The present invention relates to a method of folding an airbag for a front passenger which is deployed to protect an occupant in the event of vehicle collision. More particularly, the airbag for protecting a front passenger, can accomplish suitable deployment for sufficiently restraining an occupant and is improved to deploy smoothly.
FIGS. 4(A), 4(B) and 4(C) are views showing an airbag for a front passenger (hereinafter, referred to as "passenger airbag" or "airbag") when it is deployed, which is folded in one of conventional folding methods. FIG. 4(A) is a side view for showing the passenger airbag 1 accommodated in an airbag case 2. In these figures, the right hand side is a windshield side and the left hand side is an occupant side or counter-windshield side.
In FIG. 4(A), right and left end portions or loose portions 5G, 5F of the airbag 1 are folded in bellows, and a tip portion or wound portion 5E is wound in such a manner that a windshield-side surface becomes the outer surface of the wound airbag. After that, the entire airbag 1 is accommodated in the airbag case 2. The airbag 1 is fixed to an inner surface of an opening of the airbag case 2 by fittings (not shown). The loose portions 5F, 5G are formed by folding in bellows at both windshield side and counter-windshield side. Inside the airbag case 2, an inflator 4 for generating a gas for deploying the airbag is disposed. The airbag case 2 is installed in an instrument panel 8 in FIG. 4(B) in front of the front passenger seat within a vehicle.
The passenger airbag as shown in FIG. 4(A) starts to deploy through an upper portion of the instrument panel and is inflated upward. The description will now be made as regard to the configurations of the passenger airbag, during its deployment where it is inflated upward, which is folded as shown in FIG. 4(A).
FIGS. 4(B) and 4(C) are views showing the configurations of the passenger airbag during its deployment which is folded in the conventional manner shown in FIG. 4(A). In FIG. 4(B), as the gas from the inflator 4 disposed in the airbag case 2 flows into the airbag 1 as shown by arrows, an airbag cover 9 attached to the instrument panel 8 is broken by the gas pressure in the airbag 1 and the airbag 1 is deployed above the instrument panel 8. At this point, the gas first flows into the loose portions 5F, 5G on the windshield side and the counter-windshield side, prior to the wound portion 5E of the airbag 1. That is, the airbag 1 is first deployed at the loose portions 5F, 5G and, after that, deployed at the wound portion 5E.
However, according to the passenger airbag which is folded in the conventional method as described above, the loose portions 5F, 5G are first deployed so that the wound portion 5E is pushed up by the deployed loose portions 5F, 5G. This means that the wound portion 5E is kept in the folded state during its upward movement.
The wound portion 5E is pushed upward (arrow A) while it is still in the folded state as shown in FIG. 4(C), so that the portion 5E strikes the windshield 3 in the wound state. With this deployment process of the airbag 1, there is a possibility that the windshield 3 is subjected to an undesirable local pressure. In order to prevent the application of the undesirable local pressure on the windshield 3, various measures have been taken, for example, reducing the output of the inflator 4, adjusting the mounting position of the airbag 1 and/or the angle for mounting the airbag case 2, and increasing the strength of the windshield 3. These measures limit the free designing of the airbag and the instrument panel and, in addition, increase the cost.
The present invention has been made in order to solve the above problem, and an object of the invention is to provide a passenger airbag, which can provide stable and smooth deployment to securely and sufficiently restrain an occupant.
Another object of the invention is to provide a passenger airbag as stated above, which prevents an undesirable local pressure from being applied on the windshield 3 without increasing the cost.
A further object of the invention is to provide a folding method of a passenger airbag as stated above.
Further objects and advantages of the invention will be apparent from the following description of the invention.